In the field of wheel speed sensors designed for sophisticated vehicle control systems one important issue relates to a reliable control over internal functions of wheel speed sensors. In automotive industry wheel speed sensors are used for ABS (anti-lock braking systems), gearbox and transmission applications, but also for indirect tire pressure monitoring systems (relying on deviations in the rotational speed between two wheels). The requirements in the automotive industry have been increased in recent times and, in particular, the robustness with respect to electrostatic discharge and electromagnetic compatibility has been increased. This, in turn, implies an increased demand for a reliable error management enabling rotational speed sensors to indicate internal failures or malfunctions reliably and promptly to a control unit, as for example the electronic control unit (ECU) used in automotive applications.